Papers by Keyword: Stability Analysis

Abstract: In this article, a direct numerical method is developed to solve two-dimensional interaction problems of wave and floating body with ADINA software. Motion’s equation of the floating body and hydrodynamic parameters are expressed based on potential flow theory. The force and response on the floating body boundary is described in terms of linear minor wave theory. The numerical test is carried out. The result intuitively shows the dynamic response and the stability of floating body under incident waves.

Abstract: The analysis of variance (ANOVA) is a classic tool for an identification of discreet factors impact on the measurable output by a specific decomposition on a total variance according to the scheme proposed by R.A Fisher in the 1920s. There are many explicit and implicit assumptions required as a preliminary of ANOVA computations. The ANOVA computations scheme is well known and implemented in many types of software but all estimations are provided with the assumption of a normal and homoscedasticity distribution of the noise disturbing the output. Computation procedures produce a single number output (e.g. F statistics, p-Value) without any analysis of their own dispersion. This paper analyzes the ANOVA output using the bootstrap approach. It seems to be the most convenient as a data-driven procedure. The source raw data are taken from the image analysis conducted during the investigation of the impact of the ceramic layer thickness on the wax pattern assembly of a turbine blade on the (γ+γ’) eutectic in the IN713C superalloy.

Abstract: Based on capillary tension, surface free energy and elasticity theory, a collapse model of nanopore in C-S-H gel was created in hardened cement pastes. The stability of pore was analyzed by Gibbs free energy theory. The results show that, the capillary is more stable while the capillary is grater and rounder in the case of the aperture changing in the nanometer scope. When the aperture is changing in the scope of micrometer, the collapse possibility of the capillary is tiny. If the capillary size is fixed, the capillary is more stable while the elastic modulus of hydrated products is higher.

Abstract: In the present paper is presented a numerical simulation of an electro-hydro-mechanical system of adaptive transmission of mechanical power. This system is based on a hydraulic circuit consists of a hydraulic pump with constant flow and a hydraulic motor with variable flow ordered so that the pressure in the circuit to remain constant. For a variation of the ramp and step signal sources of loads, are presented the main features of operation of adaptive transmission. Analysis of dynamic stability of mechanical transmission is made through the linear analysis with Bode diagrams. Simulation of transmission operation is performed with AMESim.

Abstract: When calculating the dam slope failure process, traditional strength reduction method doesn't consider the difference of decay rate between cohesion and internal friction angle and discount the strength parameters for all elements. This paper uses two different reduction factors for material strength parameters, slope cohesion and internal friction angle. Based on the yield approach index criterion, we change the reduction region in time and put forward a double safety factor of dynamic local strength reduction method for engineering analysis of dam slope stability.

Abstract: Through the analysis of the external factors including the engineering geological and hydro geological conditions of the collapse and internal factors, the collapse is divided into 6 period of different areas, and the paper determine the types of collapse and make stability analysis one by one. Then the steady state is determined. Based on the protection of the combination of bank collapse object, the corresponding treatment methods are put forward. A comprehensive comparison among the technical degree of difficulty, degree of environmental protection, construction and economy has been made. Eventually the implementation plan is recommended.

Abstract: The formation of a loose engineering landslide is carried on, and the comprehensive analysis on the formation mechanism of landslide is studied. The stability checking is carried out. Accordingly, the treatments are put forward.

Abstract: Slope dynamic factor of safety (FOS) under earthquake was calculated based on time history analysis method and compared with acceleration time history to analyze correspondence between them. In view of the fact that earthquake is a dynamic process, this paper proposed that three respects can be considered to analyze the slope stability rather than adopting a single FOS value. Firstly, the variation trend of the FOS time history can be combined with the forces on key points to analyze slope stability. Secondly, the displacement and stress vector fields can be adopted to evaluate the final slope stability. Thirdly, the variation trend of the displacement and velocity time history can be used as well. The above methods are applied to Beihoushan landslide in Hanyuan in Wenchuan earthquake to evaluate slope stability under earthquake and the analysis shows that the slope is stable as a whole.

Abstract: A LASER Guided Missile System is used in most military operations for its known accuracy. But, a typical such system has a high order of non-linear characteristics and thus, a highly unstable performance. Such systems have a guidance and control system which acts as a flying servomechanism - an electromechanical device that positions an object according to a variable signal by reducing the error between two quantities. The guidance portion of the system develops the variable input signal. The input signal represents the desired course to the target. The missile control system operates to bring the missile onto the desired course. Thus, the output of the guidance and control system is the actual missile flight path. This paper dwells into the idea of using a PID Controller as part of the ‘control system’ in the missile, introducing stability in the system by reducing the error. The controller has been simulated using Simulink environment of MATLAB. The robustness of this PID controller, for different non-ideal environments, is tested post – tuning and is analysed based on performance criteria like overshoot, settling time etc.

Abstract: China is facing two major problems from energy shortage and environmental pollution due to the rapid development of economy. The exploitation of clean and renewable energy brings hope to China. Owning wide seas, China is rich in offshore wind energy and current tidal energy. This paper considers installing turbines on the platform of the generator of floating wind turbines, designing a floating co-generator of wind and tidal current to achieve co-generation of wind turbines and turbines. Firstly, this paper conducts a preliminary design of three-column floating wind-current generator. Then this paper uses the GeniE and HydroD modules of SESAM to model the co-generator and perform stability analysis. Finally, based on the Catenary Theory, this paper designs mooring system for the co-generator and uses AQWA to perform time-domain analysis, ensuring the steady operation of the co-generator at working seas.